Grantee Research Project Results

The Toxic Dinoflagellate, Pfiesteria piscicida, as a Potential Biosensor of Estuarine Stress

EPA Grant Number: R825551
Title: The Toxic Dinoflagellate, Pfiesteria piscicida, as a Potential Biosensor of Estuarine Stress
Investigators: Burkholder, Joann M. , Shumway, Sandra E. , Rublee, Parke
Institution: North Carolina State University , Long Island University - Southampton College , University of North Carolina at Greensboro
EPA Project Officer: Packard, Benjamin H
Project Period: May 19, 1997 through May 18, 2000 (Extended to May 18, 2001)
Project Amount: $500,000
RFA: Harmful Algal Blooms (1997) RFA Text | Recipients Lists
Research Category: Aquatic Ecosystems , Water Quality , Water

Description:

A recent cosmopolitan rise in the frequency and spatial extent of toxic phytoplankton blooms suggests that these noxious species can significantly reduce estuarine and marine fishery resources. In the early 1990s we discovered a new genus of "ambush-predator" dinoflagellate, Pfiesteria, with known species having a complex life cycle of at least 22 stages including persistent ichthyotoxic amoebae and flagellates. Pfiesteria-like dinoflagellates are common in previously examined mid-Atlantic and east Gulf Coast estuaries, and likely are widespread throughout temperate and subtropical eutrophic waters. The apparent ubiquitous occurrence and abundance of these stages in estuarine waters and sediments, their voracious phagotrophy on photosynthetic/heterotrophic microbial prey, and their lethality to finfish and shellfish point to a major role of Pfiesteria species in the trophic balance and productivity of estuarine food webs.

In the proposed research, we plan to (i) examine controlling influences of both inorganic and organic N and P on growth of Pfiesteria piscicida zoospores (toxic and nontoxic), when given food resources as dissolved or particulate (algal) carbon; (ii) improve detection of flagellated lated, amoeboid, and encysted stages of P. piscicida by developing and testing species-speci- fic molecular probes; and (iii) assess Pfiesteria's acute and sublethal/chronic impacts on life stages of commercially / ecologically valuable shellfish species.

Approach:

Nutritional (N,P) controls on Pfiesteria zoospore abundance and stage transformations will be examined through a series of experiments under controlled laboratory conditions, in which nutrient gradients will be imposed with vs. without supplementary carbon sources (dissolved organic carbon as acetate; particulate organic carbon as algal prey) under controlled laboratory conditions. We plan to expand upon research progress to date in developing fluorescentlabeled molecular probes to enable rapid, routine detection of Pfiesteria's major life cycle stages in fish kill and ulcerative fish epizootic sites. And, in a second series of laboratory experiments, we will compare acute and sublethal/chronic impacts of P. piscicida on survival and selected metabolic processes in representative shellfish species.

Expected Results:

This research will enhance our ability to detect Pfiesteria-like dinoflagellates in early diagnosis of aquaculture facilities contamination, as well as in the wild during fish kills and epi- zootics. It will also strengthen our understanding about influences of anthropogenic nutrient loading on Pfiesteria-like dinoflagellates, and their ecological, physiological, and cytotoxicological effects on shellfish. The insights from our data will improve strategies for evaluating chronic sublethal effects of shellfish exposure to these toxic dinoflagellates, and will also evaluation of their potential utility as biosensors of estuarine stress from cultural eutrophication.

Publications and Presentations:

Publications have been submitted on this project: View all 19 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 16 journal articles for this project

Supplemental Keywords:

estuaries, nutrients., RFA, Ecosystem Protection/Environmental Exposure & Risk, Scientific Discipline, Water, Waste, algal blooms, Ecological Indicators, Ecological Risk Assessment, Ecosystem Protection, Ecosystem/Assessment/Indicators, Contaminated Sediments, exploratory research environmental biology, Environmental Microbiology, Ecological Effects - Environmental Exposure & Risk, Ecological Effects - Human Health, Hydrology, Nutrients, Chemical Mixtures - Environmental Exposure & Risk, Ecology and Ecosystems, phytoplankton, phytoplankton dynamics, watershed management, fish lesions, contaminated sediment, water quality, estuaries, biosensor, aquatic ecosystem, heterotrophic microbial prey, nutrient kinetics, ecosystem stress, pfiesteria piscicida, ecological exposure, estuarine stress, food web, algal growth, estuarine ecosystems, dinoflagellate, dinoflagellates, estuarine food web, nutrient transport, harmful algal blooms, phytoplankton blooms, pfiesteria, nutrient cycling

Progress and Final Reports:

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.